Back digger



D.16,193o. 1 l AORLOFP '1,785,492

BACK DIGGER- Filed April 22, 1929 WOW duim/wu,

lo into the trench durin Patented Dec. 16, 1930 U1\11TED .STATESPATENTOFFICE 7 ARTHUR ORLOFE, or GREEN RAY, WISCONSIN, AssIeNoR TONORTHWEST ENGINEER- I." ING CORPORATION, OE GREEN RAY, WISCONSIN, ACORPORATION OE WISCONSIN p l RACK D I'GGER y Application filed April 22,

The invention relates" to excavators and more particularly those of thetype usually called pull shovels, trench hoes or back digers. M Y g Theusual'typefof'pullshoveh' wherein the hoist cable extendsfout totheouter endrof the boom and' over sheaves at the end of the boom, orassociated with .the dipper handle so that 'said hoisting lineand itssheaves get "digging, present a fruitful source of trou le inasmuch asit is impossible-to keep dirt and grit from falling into the sheaves,with resultant troubles due to rapid wearing of the moving parts,particularly the cable, as when small stones get between the cable andsheaves, cutting and consequent breakage are apt to result. According tothe present invention these disadvantages are overcome by providing ahoisting cable separate from the clipper stick to raise and lower theboom and to utilize the compression forces transmitted through the boomdue to the weight of the boom, clipper and dipper handle-to effect theoperation of 2,5 other means which move the dipper and its stickangularly relative'to the boom.

' A further object of the invention is to provide a novel arrangementfor swinging the dipper and its handle relative to the boom l 30 whereinthe desired effect is obtained of having less outwardswinging force uponthe flipper handle occur when the boom is lowered into the trench than'when it is elevated in the dumping position. This is obtained in thepresent arrangement becausein the upper position the weight of theclipper and its` handle tendsto move the dipper inward while in theextreme lower position this weight tends tovswing the dipperv outward.

Consequently, in the lower positions less additional force is requiredto swing the dipper voutwardly to a certain angle with respect to .theboom.

A further Object of the invention is to provide a swinging support forthe the piv- 1929. serial No. 357,067.

otal mounting of the boom which support is .i

connected-by cablefwith the dipper handle :to effect an angularfoutward:movement-Of the dipperand flipper handle' relativegto the vboom indifferent positions thereof and under P' the control of another Acable.which also feffects .an'inwardswinging movement of the dipper and itshandle relative to the'boom.

The invention further consists inthe several features hereinafter setforth and more particularly defined by claims at the conclusion hereof.-v i The drawing shows an elevation view of an excavatorV embodying theinvention.

Referringi'to the drawings the numeral 4? designates the traveling baseof the machine equipped 'with endless propelling treads 5 driven inknown manner from a suitable prime mover 7 on the rotating base 6 of themachine, 8 a swinging boom pivot support or lever pivotally connected atone end bya pin 9 to the base 6 and having the boom 10 pivotallyconnected to said lever at an intermediate point by a pin 1l wherebysaid boom is mounted for up and down movements relative to themachine'base'and also for angular movements relative to said support 8.

A dipper handle or stick, 12 isfpivotally 'connected intermediate itsends by a pin 13 to the outer end of the boom vandcarries a dip- -per 14facing toward ythe machine and in operative position relative to the'trench and to effect the retention of the load in the'dipper when theboom is in an elevatedposition, or to retain the dipper in any .desiredangular 'position against forces tending to move it outwardly relativet0 the boom.

For raising and lowering the boom, dipper and dipper handle, a hoistingcable 20 passes from the hoist drum 21 over a guide sheave 22 on theshear leg 23, thence around a sheave 24 mounted on the medial portion ofthe boom or back from its forward end and is dead ended on the machine,as by a connection with said shear leg. Thus winding in on the hoistingcable raises the boom l0 and the parts carried thereby and paying out ofthis cable lowers these parts. f .ff

The drums 17 and 21 are equipped as usual with brakes and clutches tocontrol theirv operation.

The free end 25 of the boomsupport enlever 8 has a'link' or pullconnection "with 'the up' per end of the dipper handle. This centreeltion preferably comprises a cable 26 whose" ends are suitably pivotallyconnected-respeotively lvith said end 25 and with said handle, -as at 2AvW'ith this construction when the boom is in a raised position 'aportion of its'weight and that of the 4dipper and dipper handle' willreact against the rocking or pivotal lever or supprtlS through which it`is connected-to the base of the machine and willtend to swingI the-treefendv of 'said lever "8 inwardly and through this reaction exertapull on Vthe cable 26'toward the'machine, which is of a length tothereby produce a pull onthe dipper handle which acts to swing thedipper handle and -dipper outward relative to theboom, as shown in fulllines in the drawing.' When, however, the dipper is lowered into thetrench, the weight of the boom tends to pull the lever 8 outward, withthe result that there is less tendency to swing the dipper, outward, asshown by the dotted line position of the parts, and under theseconditions a hauling in of the drag line I6 causes the inward swinging0r digging movement of the dipper and a retention of the dipper in itsinward position relative to the boom after digging permits the hoistingcable to be operated to raise the boom and dipper to an elevatedposition and the swinging of the boom to a position of discharge,'.atwhich time a paying out of the drag line permits the lever 8 and cable26 to effect :the outward movement of the dipper handle and dipper Vtodischarge its load or, if desired, the dipper may be provided with abottomdumping door, long well known in excavators, for discharging itsload, or other forms of discharge means for the dipper may be fused, 4 i

From the foregoing description it will be noted that I have provided apull shovel constructionin which the' component of weight of the parteexerted along the boom is used to e-lect' movement of means operativelyconnected tothe dipper handle to effect shifting y movements ofthedipper and dipper stick and that such component has a greater effectwhen the boom is in a raised position than when it is in a lowered,digging position.

I desire it to be understood that this invention is not to be limited toany particular form or arrangement of parts except insofar as suchlimitations are included in the claims or necessitated by the prior art.

What I claim as my invention is:

1. In an excavating machine, the combination of a base, a movable boomsupport mounted ,on vsaid base, aboom Apivotally mounted on said supportfor .up and down movements and so that its pivot moves relative to thebase of the machine during the diggingV cycle, a dipper handle pivotallymounted on the outer end -portionof said boom and carrying a dipperworking toward themachine during digging, a hoisting cable associatedwith the boom, and means associated with said support and moved therebyfunder the forces exerted thereon bythe boom for effecting shiftinmovements of the dipper and dipper han le relative to' `|the boom.

2. In an excavating machine, the combination ofa support .pivotallyAmounted .on :the

machine, aboom Ipivotally mounted/0n said Lsupport for up and downmovements-.and

for moving saidsupport during the dig ing cycle,` adipper handlepivotally mounte' on the outer end portion of said boom and car'- ryinga dipper working toward the machine duringdigging, a hoisting cableassociated with the boom, and pulling means associated with said supportand dipper handle for shifting the dipper outwardly relative to the boomunder the shifting action of said boom on said support.

3. In an excavating machine, the combination of a movable boom support,a boom mounted on said support for up and down movement and for movingsaid support during the digging cycle, a dipper handle pivotally mountedon the outer end portion of said boom and carrying a dipper workingtoward the machine during digging, a hoisting cable associated with theboom, means associated with said support and moved thereby under forcesexerted thereon by the outward shift'of said dipper and for swinging itinwardly toward'the boom.

4. In an excavating machine, the combination of a supportpivotally'mounted on the machine, a boom pivotally .mounted on saidsupport for up and down movements and for moving said support, a: dipperhandle pivot-- ally mounted on the outer end portion of said boom andcarrying" a 'clipper working toward the machine duringdiggng, a hoistingcable associated with the boom, pulling means associated with saidsupport and dipper handle for shifting the dipper outwardly relative'tothe boom -under the lshifting' action of said booml n 'said support, andseparately cotrolled means opposing the outward shift of said dipper and'for swinging it inwardly toward the boom.

5. In an excavating machine, the combination of a support pivotallymounted at one end on the machine, a boom pivotally mounted on saidsupport, intermediate its ends, for np and down movements and for movingsaid support, a dipper handle pivotally mounted on the outer end portionof said'boom and carrying a dipper working toward the machine duringdigging, a hoisting cable associated with the boom, and a cableconnection between the free end ot said support and the dipper handlefor shifting the dipper and dipper handle outwardly relative to the boomunder the shifting action of said boom on said support.

6. In an excavating machine, the combination of a boom mounted for upand down movements, a dipper handle pivotally mounted on the outer endportion of said boom and carrying a dipper Working toward the ma.- chineduring digging, a hoisting cable for raising and lowering the boom, amovable supporting means for the boom for converting the weightcomponent of the boom acting along the same into a pulling force exertedon the clipper handle for swinging the dipper outwardly relative to theboom, and means -tor transmitting this pulling force t0 said dipperhandle.

7 In an excavating machine, the combination of a boom mounted for up anddown movements, a dipper handle pivotally mounted on the outer endportion of said boom and carrying a dipper working toward the machineduring digging, and means including a movable support for the boomoperatively connected te saiddipper handle and actuated by a weightcomponent of the boom Jfor swinging the dipper handle and dipperoutwardly relative to the boom, said means under the action of the boomexerting a lesser swinging force upon the dipper'handle when the boom islowerei into digging position than when said boom is in an elevatedpesition.

8. In an excavating machine, the combination ot' a base, a swingingboom, a dipper handle pivetally mounted on the onter end portion of saidboom and carrying a dipper working toward the machine during digging,movable means for supporting the inner end of the boom tor movementrelative to said base, means for moving the dipper handle relative tothe boom by said supporting means dni-ing the digging cycle, and meansfor raising and lowering said boom.

9. In an excavating machine, the combination of a base, al leverpivotally mounted on said base, a boom pivotally mounted on said leverfor up and down movements and for moving said lever during the diggingcycle,

' a dipper handle pivotally mounted on tne outer end portion of saidboom and carrying a dipper Working toward the machine during digging, ahoisting cable associated with the boom, and means operativelyconnecting said lever, at a point spaced from the connection of saidlever to said base, to said dipper handle for eiecting shiftingmovements of the dipper and dipper handle relative to the boom on themovement of said lever.

In testimony whereof, I alix my signature.

ARTHUR ORLOFF.

